Processing system with protective device for secure processing table

ABSTRACT

The invention relates to a moving assembly for a working system, said assembly including:  
     a boom ( 22 ) extending along an axis between first and second ends ( 31, 33 ) and a working head ( 30 ) mounted on said boom;  
     first and second lateral obstacle sensor systems ( 40, 42, 77, 83, 90, 92, 100, 102 ) mounted at each end of the boom; and  
     respective first and second optical systems ( 50, 52, 60, 62, 75, 79 ) fixed to the first and second lateral obstacle sensor systems to detect the presence of an obstacle on the path of the boom and movement and/or deformation of one lateral obstacle sensor system relative to the other one.

TECHNICAL FIELD AND PRIOR ART

[0001] The invention relates to a system comprising a processing or worktable over which a boom can move. The boom supports a head equipped withone or more tools. In a preferred application, the head is equipped withone or more cutting tools.

[0002] The invention also relates to a safety system, in particular ofthe type intended for work tables, for example cutting tables.

[0003] The invention applies to cutting machines and to machines forprocessing sheet materials, in particular labeling systems or machinesfor printing sheet materials.

[0004] Cutting tables are used to cut flexible materials, for exampletextile materials, using a penetrating blade or laser beams, forexample.

[0005] They are more particularly intended for use in the furnishing ortailoring industries, especially in prototyping and making-to-measure,and for use in some applications for cutting technical fabric.

[0006]FIGS. 1A and 1B show one example of a cutting table.

[0007] The cutting table includes a table 2 generally comprising cuttingsupports 17, 19 fixed or stuck to boxes 18, 20 (FIG. 1B). The boxes areisolated from each other and supported on a system of legs 4-1, 4-2, 4-3(FIG. 1A) and stringers (not shown in the figures).

[0008] A suction system is fixed under each box. These cutting supportplates are hard and porous.

[0009] The tops of the boxes, on which the cutting plates rest, areperforated. The suction system therefore holds down the material throughthe boxes and the cutting plates.

[0010] Two rails 8 and 10 are fixed to the boxes 18 and 20 on respectiveopposite sides of the table and guide a moving boom 22 as it moves ineither direction along the longitudinal axis X of the table between afront area 12 and a rear area 14 of the table.

[0011] The boom 22 is equipped with a cutting head 30 mounted on acarriage 35 movable along the boom in a direction Y substantiallyperpendicular to the direction of the axis X. The cutting head isequipped with a cutting blade 32 for cutting out required shapes from aflexible material, for example a textile material, placed on the table.

[0012] A control console 34 generally including a microcomputer (PC)controls the starting of cutting and movements of both the boom 22 andthe cutting head 30 to produce pieces from the flexible material. Anoperator controls the system by means of a keyboard and a display screenwhich enable the operator to display the lay out of parts to be producedfrom sheets of flexible material.

[0013] This kind of cutting system is accessible from both sides, aswell as from the front and the rear of the table, to enable maintenanceoperations, bringing up and loading a flexible material, offloadingpieces cut out from the material, and monitoring cutting.

[0014] This kind of cutting table is generally relatively long, forexample from 3 to 18 meters long.

[0015] Thus an operator 16 generally monitors cutting by moving aroundthe table. Movement of the boom 22 along the axis X can impact laterallyon the operator. This raises a problem of safety in the working andmaintenance area around the cutting machine.

[0016] A first solution to this problem consists of equipping the movingboom with lateral safety bars 40, 42 which are moving relative to thesupport carriages 31, 33 at the ends of the boom.

[0017]FIG. 2 shows in more detail the mounting of a protection bar 40 onits carriage 31. The bar passes through guide members 53, 57 fixed tothe carriage 31. An electromechanical sensor 41 is also fixed to thecarriage 31. One end of the sensor locates in a notch 39 in the bar 40.The bar 40 is moved relative to the carriage 31 when it encounters anobstacle during movement of the boom 22 along the X axis.

[0018] The end of the sensor 41 then leaves the notch 39, which trips aswitch and cuts off the power supply to the drive system of the boom 22.

[0019] Although that kind of system is satisfactory in some respects, itdoes not address a number of problems. The problem therefore arises ofproposing a safer cutting system.

[0020] In particular, the above type of system cannot detect thepresence of an operator's arm or hand above one end of the boom 22. Theoperator can be sufficiently far away from the cutting table for thelateral bars on his side of the table not to strike him, in which casethe safety system is not tripped, but nevertheless the operator can havea hand or an arm positioned above the end of the boom.

[0021] What is more, the above type of prior art system cannot detect anobstacle near the boom.

[0022] An obstacle near the boom could be on the surface of the cuttingtable, for example a foreign body which could form a dangerousprojectile if struck by the boom and/or the cutting head.

[0023] An obstacle near the boom could equally well be above the surfaceof the cutting table, for example an operator's hand approaching theboom 22 or the support 35.

SUMMARY OF THE INVENTION

[0024] For the above reasons the invention provides a moving assemblyfor a system for working or processing flexible materials, especiallymaterials used in tailoring, or textile materials, the assemblycomprising:

[0025] a boom extending along an axis between first and second ends anda working head mounted on said boom;

[0026] first and second lateral obstacle sensor systems mounted at eachend of the boom, movable or deformable relative to the boom andindependently of each other in a direction (X) substantiallyperpendicular to the axis of the boom, and having an extension in thesame direction on either side of the boom ; and

[0027] respective first and second optical systems fixed to the firstand second lateral obstacle sensor systems to detect the presence of anobstacle on the path of the boom and movement and/or deformation of thelateral obstacle sensor systems relative to each other.

[0028] Lateral obstacles, or an obstacle on the path of the moving boom,are therefore detected optically.

[0029] The optical system preferably comprises one or more pairs ofemitters and sensors, with each emitter mounted on one of the lateralobstacle sensor systems and the corresponding sensor mounted on theother lateral obstacle sensor system.

[0030] In one variant, the first optical system comprises anemitter-receiver pair mounted on one of the lateral obstacle sensorsystems and the second optical system comprises a system mounted on theother lateral obstacle sensor system to reflect a beam emitted by theemitter towards the receiver.

[0031] Optical systems for detecting obstacles on the path of the boomcan additionally be mounted on the boom, and rigidly or deformablyconnected to it.

[0032] The optical systems mounted on the boom and fixed relative to thelateral obstacle sensor systems then define a safety volume around theboom.

[0033] The first and second lateral obstacle sensor systems may bemovable independently of each other relative to the boom, in a directionsubstantially perpendicular to the axis of the boom, with an extensionin the same direction on either side of the boom.

[0034] Respective first and second movement sensor systems, for exampleelectromechanical sensors, may be associated with the first and secondlateral obstacle sensor systems.

[0035] The optical systems mounted on the lateral obstacle sensorsystems then constitute a second level of safety measures in the eventnon-operation of the movement sensor system associated with the firstand/or second lateral obstacle sensor system in response to detection ofa lateral obstacle.

[0036] In another embodiment, the first and second lateral obstaclesensor systems comprise at least one support that can be deformable in adirection perpendicular to the axis of the boom and is mounted on thefirst and/or second lateral obstacle sensor system.

[0037] Furthermore, optical systems can be fixed to the deformablesupport to detect obstacles on the path of the boom and to detectdeformation of the deformable support in said direction perpendicular tothe axis of the boom.

[0038] In another embodiment, the first and/or the second lateralobstacle sensor system has a first part movable in said directionsubstantially perpendicular to the axis of the boom and a second partarticulated to the first part and able to rotate about an axissubstantially perpendicular to said direction, and either the firstoptical system or the second optical system is fixed to this secondpart.

[0039] In another aspect, the first lateral obstacle sensor system hasfirst and second parts movable relative to each other and each part isprovided with an optical system for detecting the presence of anobstacle on the path of the boom and movement of one of the lateralobstacle sensor systems relative to the other one.

[0040] The second lateral obstacle sensor system may additionally havethird and fourth parts movable relative to each other, with each partprovided with an optical system for detecting the presence of anobstacle on the path of the boom and movement of one of the lateralobstacle sensor systems relative to the other one.

[0041] An optical element is advantageously disposed on an optical pathdefined between the first and second lateral obstacle sensor systems.This optical element is additionally connected to the cutting head andits position relative to the latter changes if it encounters an obstacleduring movement of the boom and the cutting head.

[0042] In a further aspect, the cutting head includes a protective coverthat protects it when closed and which intercepts an optical pathdefined between the first and second fixed optical systems on the firstand second lateral obstacle sensor systems.

[0043] The invention also provides a system for processing flexiblematerials, the system comprising:

[0044] a work support or table;

[0045] one or more moving assemblies as described hereinabove; and

[0046] a system for moving said moving assembly or assemblies on thework support or table.

[0047] The moving assembly, with its safety systems, is suitable forwork tables whose width is from 0.3 meters (m) to 5 m, for example, andfor a maximum speed of the boom from 0 to 3 meters per second (m/s) (180m/min), for example.

[0048] The work table can be fixed or moving, in the latter caseincorporating a conveyor.

[0049] The working head supports a cutting tool and/or a printing tooland/or a labeling tool and/or a perforation tool, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The features and advantages of the invention become more apparentin the light of the following description, which relates to embodimentsprovided by way of non-limiting and explanatory example only, and refersto the accompanying drawings, in which:

[0051]FIGS. 1A and 1B show a cutting table structure.

[0052]FIG. 2 shows a prior art lateral impact sensor system.

[0053]FIGS. 3A to 9 show various embodiments of the invention.

[0054]FIG. 10 shows diagrammatically a table incorporating a movingconveyor.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0055] A moving assembly in accordance with the invention is describedfirst with reference to FIG. 3A.

[0056] In this figure, as in the other figures, the reference numbers22, 31, 33, 40, 42 designate the same items as in FIG. 1A.

[0057] An emitter cell 50 is placed at one end of the safety arm or bar40. The cell comprises an infrared laser diode, for example, and emits abeam 51. A receiver cell 52 receives the beam 51.

[0058] The output signal of the cell 52 is connected to the drive motorof the boom 22. A variation in the intensity of this signal stops theboom 22.

[0059] Provided that the bars 40, 42 remain in the same initialposition, and that no object interrupts the path of the beam 51, theoutput signal of the cell 52 remains constant and the boom continues tomove.

[0060] The presence of a lateral obstacle causes relative movement ofthe bars 40, 42 and varies the output signal of the cell 52. Thisresults in cutting off the power supply to the power circuit of thecutting machine; the braking module for the boom drive motors isactuated.

[0061] Similarly, as soon as an obstacle, for example the operator'shand, intercepts the path of the beam 51, the output signal of the cell52 varies, with the same consequences.

[0062] In fact, the systems driving the boom 22 are stopped as soon asthe optical systems 50, 52 are no longer aligned or as soon as the pathof the beam 51 is interrupted.

[0063] Furthermore, each of the carriages 31, 33 can be constructed inthe manner described above with reference to FIG. 2, with anelectromechanical switch 41 inserted in a notch 39 in the correspondingbar 40, 42. The switches detect any movement of the bars 40, 42 relativeto the carriages 31, 33.

[0064] Each of the bars 40, 42 is then initially in the position shownin FIG. 2: each electromagnetic switch 41 is closed and the drive motorsof the boom 22 drive movement thereof over the surface of the cuttingtable 2 in the normal manner (see FIG. 1A).

[0065] Immediately one of the two bars 40, 42 collides with a lateralobstacle, for example an operator standing beside the table 2, the baris moved relative to the corresponding end of the boom. The end of theelectromechanical sensor leaves its notch, switching off the boom drivesystem. What is more, the output signal of the cell 52 varies suddenly,which also results in cutting off the power supply to the power circuitof the cutting system, and the braking module for the boom drive motorsis actuated.

[0066] The electromechanical sensor and the optical systems 50, 52constitute a redundant safety system. If the receiver is no longerfacing the emitter because of a collision with a lateral obstacle, theoutput signal of the cell 52 is modified, also cutting off the powersupply to the power circuit of the cutting system and actuating themotor braking module.

[0067] The systems driving the boom 22 are therefore stopped as soon asone of the switches 41 leaves its notch, as soon as the optical systems50, 52 are no longer aligned, or as soon as the path of the beam 51 isinterrupted.

[0068] As shown in FIG. 3A, another emitter 60-receiver 62 pair can beplaced at the other end of the bars 40, 42, this other pair alsoproviding the functions of detecting obstacles at the other end of theboom 22 relative to the emitter 50-receiver 52 pair and detectingrelative movement of the bars 40, 42. The second emitter-receiver pairoperates in exactly the same way as the first pair 50-52.

[0069] Consequently, in the normal situation, the relative positions ofthe emitter cells 50, 60 and the receiver cells 52, 62 are such that thebeam is transmitted correctly.

[0070] The cutting machine is stopped if there is an obstacle on thetable 2 which intercepts one of the beams 51, 61.

[0071] On detection of a lateral obstacle, the relative position of theemitter and receiver cells is modified and the machine is stopped, asalready explained hereinabove.

[0072] If the system further includes an electromechanical safetysystem, for example of the type described hereinabove with reference toFIG. 2, the optical sensor system 50, 52, 60, 62 again constitutes aredundant safety measure.

[0073] An emergency stop is therefore effected if mechanical interactionwith one of the bars 40, 42 changes the state of the electromechanicalswitch. Because of this mechanical interaction, the cells 50 and 52 (andwhere applicable the cells 60 and 62) are no longer aligned and the beamis no longer transmitted correctly.

[0074] In a variant (FIG. 3B), the emitter 52 is, or the emitters 52 and62 are, fixed to the boom 22 or to its ends 31, 33, and the same appliesto the sensor 50 and, where applicable, the sensor 60. Reflectors 53,63, 65, 67 orient the beam as required.

[0075] In another embodiment, shown in FIG. 4A, an emitter 64 and areceiver 66 are placed on the same bar 42. An infrared beam emitted bythe emitter 64 is reflected onto the sensor 66 by a reflective member 68fixed to the other bar 40.

[0076] Once again, any obstacle on the path 70 of the infrared beamsuddenly modifies the output signal of the sensor 66, which stops thedrive system of the boom 22. If one of the bars 40, 42 encounters anobstacle it is moved relative to the corresponding end 31, 33 of theboom. The beam emitted by the emitter 64 is then no longer reflectedtoward the sensor 66, which also stops the drive system of the boom 22.

[0077] In a variant, shown in FIG. 4B, the emitter 64 and the sensor 66are fixed to the boom itself (in this instance to one of its ends) andthe beams are reflected by mirrors 67, 69 mounted on the bar 42.

[0078] The embodiment of FIGS. 4A and 4B is easier to manufacture thanthat of FIGS. 3A and 3B because it necessitates modification of only oneof the arms (the arm 42) and the reflector 68 can simply be stuck to thearm 40.

[0079] In FIGS. 4A and 4B, if an electromechanical sensor system is alsoprovided, the emitter-reflector-sensor combination then provides aredundant safety measure operative in the event of failure of anelectromechanical switch.

[0080] In all the variants described above, placing the emitter andreceiver cells on the bars 40, 42 limits the inaccessible area on eitherside of the boom 22 to the minimum strictly necessary. Thus bringing upmaterial can be managed efficiently in the area 14 of the system andlikewise offloading in the front area 12 of the system and monitoring ofcutting. In particular, monitoring of cutting may necessitate manualintervention on the part of the operator 16, at a location which, at thetime, is far from the position of the boom and the cutting head. Suchintervention does not necessitate interruption of cutting, which isinterrupted only if the operator's hand or arm crosses one of the beamsor one of the optical paths 51, 61 or 70. Thus the moving assembly inaccordance with the invention is efficient and compatible with a highspeed of the boom 22, from 0 to 3 m/s maximum.

[0081] Likewise, the presence of an object on the cutting table 2interrupts cutting only if the object interrupts one of the beams or oneof the optical paths 51, 61 or 70. This enables an operator to removethe object from the surface of the cutting table 2 before it interfereswith the protection optical beams or paths, without interruptingcutting.

[0082] In another embodiment, shown in FIG. 5A, one or more emitters 72are mounted on the moving boom, for example at each of its ends, eachemitter 72 being associated with a sensor 74 with which it defines anoptical path 78.

[0083] The connections 73, 75 by which the emitters 72 and the sensors74 are connected to the boom can be rigid or deformable, in particulardeformable in the direction of an axis X perpendicular to the axis ofthe boom.

[0084] An obstacle on one of the optical paths 78 modifies the outputsignal one or more of the sensors 74. This stops the drive system of theboom and the cutting head and causes cutting to be stopped.

[0085] As can be seen in FIG. 5A, the optical paths 78 pass over thecarriage 35 which carries the cutting head 30. Accordingly, one of theoptical paths 78 is interrupted if an operator attempts to work on thecutting head, the system 35 carrying the cutting head or the boomcarrying the system 35, which causes the machine to be stopped, eventhough the sensor systems 40, 42 have again not detected a lateralobstacle.

[0086] The set of optical paths 51, 61, 78 defines a safety volumearound the moving cutting system or around the boom 22 and the lateralsensor systems 40, 42. This reduces the size of the inaccessible areasof the machine to the minimum volume strictly necessary.

[0087] If the connections 73, 75 are rigid, lateral obstacles aredetected by the lateral bars 40, 42 associated with theelectromechanical sensor from FIG. 2 and/or the optical systems 50, 60,52, 62.

[0088] If one or more of the connections 73, 75 is deformable in atleast the direction of the axis X, it is possible to detect the presenceof an object (for example the operator's arm) located above one end ofthe boom 22 that the sensor system 40, 42 would not be able to detect.If the object collides with one of the connections 73, 75, thetransmission of the beam to one of the sensors is interrupted, whichstops the machine in the manner already described hereinabove withreference to FIGS. 3A and 3B.

[0089] If the lateral bars are already equipped with systems fordetecting their movement of the kind described above with reference toFIG. 2 and/or FIGS. 3A to 4B, the FIG. 5A embodiment improves thedetection of lateral obstacles. It is then possible to detect thepresence of a lateral obstacle. However, it is also possible to detectthe presence of a hand or an arm above the end of the boom which thelateral bars with their sensor systems would not have been able todetect.

[0090] Once again, this embodiment allows efficient bringing up ofmaterial, offloading and monitoring of cutting. Intervention of anoperator necessitates interruption of cutting only if the operator'shand or arm crosses one of the optical paths or beams 51, 61, 78, or ifone of the lateral detection bars 40, 42 is struck, or if one of theconnections 73, 75 that is deformable in the direction of the axis X isdeformed.

[0091]FIG. 5B represents a variant of FIG. 5A in which supports 77 aremounted at each end of the boom 22. FIG. 5B shows only a part of thesystem, with which the other end can be symmetrical with respect to anaxis of symmetry of the table. The support 77 is mounted on the lateralsafety bar 42. Optical systems (only a portion 75 of which is shown)define optical paths 78 that pass over the carriage 35, as in FIG. 5A.With the paths 51, 61 these optical paths constitute a safety volumearound the moving cutting system.

[0092] The same types of event stop the drive mechanism of the boom 22as in FIG. 5A.

[0093] What is more, as in the case of the connections 73, 75 in FIG.5A, the support 77 in FIG. 5B can be deformable in the direction of theaxis X, which enables detection of lateral obstacles, and in particularthe presence of an operator's hand or arm, even if the bars 40, 42remain in their initial position.

[0094] Thus, in FIG. 5B, an operator can strike the hoop 77 at the point81 (the impact or the collision is represented by an arrow), therebydisplacing one of the sensors 75, which leads to stopping of the cuttingmachine, even though the bar 42 remains in its initial position.

[0095] In another embodiment, shown in FIG. 5C, a support 83 similar tothe support 77 in FIG. 5B is deformable in the direction X. This supportis fixed to one end of the boom 22. The lower end 85 of the support isfixed with respect to the end of the moving boom; unlike the precedingembodiments, the boom has no bar 40, 42 movable in the direction of theaxis X relative to the boom 22. Detection of lateral obstacles isensured by the flexibility or the deformable nature of the structure orthe support 83 in the direction of the axis X. As in the FIG. 5Bstructure, the presence of an object, or any other obstacle, for examplean operator's limb, which collides with the point 81, leads to thedisplacement of one of the sensors 79 or of one of the emitters (notshown in this figure), which once again leads to stopping of the cuttingsystem.

[0096] Optical systems of the emitter/sensor type can be mounted on thelower portion 85 of the support, as in FIG. 3A, to detect the presenceof objects on the surface of the cutting area.

[0097] Interruption of one of the optical beams by an operator's arm orhand also leads to stopping of the cutting system.

[0098] Instead of the hoop structure 77, 83 of FIGS. 5B and 5C, it ispossible to use a structure connected to both ends 31, 33 of the movingboom 22 and provided with optical systems such as the emitter/receiversystems 72, 74, 75, 79 of FIGS. 5A to 5C, the structure having someflexibility or capacity for deformation in the direction of the axis Xindicated in the figures. The presence of a lateral obstacle, forexample an operator's limb, leads to deformation of this kind ofstructure and to interference with the optical paths between the emittersystem and the receiver system that it carries. This interference withthe optical path varies the intensity of the signal emitted by thesensors, which again leads to stopping of the cutting system.

[0099] The above kind of structure can be used without any other lateralsensor system, in particular without the system of bars 40, 42. It canalso be combined with a system of bars 40, 42 moveable in the directionof the axis X relative to the boom 22 and tripping a system ofelectromechanical sensors, as already described hereinabove, or varyingthe signal received by one of the receivers fixed to the bars.

[0100] Combining the above kind of structure with the above kind ofsystem with safety bars 40, 42 provides very efficient lateraldetection.

[0101] In a further embodiment, the lateral bars 40, 42 for detectingobstacles can take the form shown in FIGS. 6A and 6B. A second bar 40-2rotatable about an axis or an articulation 40-3 is mounted at the end ofa first bar 40-1. The emitter 50 is mounted at the end of the portion40-2 and directs a beam across the cutting machine. If the portion 40-2encounters a lateral obstacle or suffers an impact, as represented bythe arrow A, it is caused to rotate, as shown in FIG. 6B, which deviatesthe beam emitted by the emitter 50. This again varies the output signalof the corresponding receiver (not shown in these figures) and stops thecutting system.

[0102] A lateral impact occurring along the axis of the bar 40-1,represented by the arrow B in FIG. 6B, results in tripping of the switch41, as previously, and also in stopping of the machine. If a system ofswitches of the type shown in FIG. 2 is used, the combination of theemitter 50 and the receiver 52 again constitutes a second level ofsafety measures in the event of failure of one of the switches.

[0103] With an articulation of the type shown in FIGS. 6A and 6B, it isalso possible to mount a sensor at the end of the portion 40-2. The twoobstacle sensor bars 40, 42 can therefore both be equipped with thistype of articulation at each end.

[0104]FIG. 7A shows another embodiment, in which reference numbersidentical to those in FIG. 3 designate identical or correspondingelements. An optical element 80 is placed on the path of the boom 51 andis connected to the cutting head 30 or to the carriage 35 supporting thecutting head by a connection 82. This connection is not rigid, whichallows modification of the relative position of the optical element 80and the cutting head 30 if the optical element encounters an obstacle onits path. This again modifies the output signal of the sensor 52 andstops cutting.

[0105] If no obstacle is encountered, the element 80 remains fixed inposition relative to the boom 51.

[0106] The optical element 80 can be an optical target, for example.

[0107] A variant of the above embodiment is shown in FIG. 7B (plan view)and in FIG. 7C (side view). A support 37 is placed on the carriage 35.Non-rigid connections 87 are provided at the end 59 of the support.Optical elements 80 at the free ends of the connections, such as thosementioned hereinabove in connection with FIG. 7A, are normally placed onthe path of the beams 51, 61. As shown in FIG. 7C, these connections arejoined at the top of the support 37 and preferably have a curved,circular arc or hooped shape, and thereby provide protection in the formof an “umbrella” or half-sphere around the combination formed by theworking head 30 and its support 35. The combination is preferablyrotatable about the end 59 of the support 37 and/or movable intranslation along the axis X.

[0108] Another variant of the above embodiments is shown in side view inFIG. 7D. A set of supports or hoops 89 is mounted around the head 35.The supports can preferably be moved in translation along the axis X,for example by a rectilinear bar 91 and a system 97 for guiding the bar.Optical elements 80 at the ends of the supports are situated on thepaths of the beams 51, 61. The envelope defined by the hoops is aportion of a half-cylinder.

[0109] In the above variants, the relative position of one of theoptical elements 80 and the cutting head 30 is modified if the opticalelement support encounters an obstacle on its path. This again resultsin modification of the output signal of one of the sensors and stoppingof the machine.

[0110] If no obstacle is encountered, the elements 80 remain fixed inposition relative to the beams 51, 61.

[0111] The above embodiments can be combined with either of theembodiments described with reference to FIGS. 5A and 5B. Also, theemitter and/or the sensor can be fixed to the boom itself, a system ofmirrors directing the boom correctly, as in FIG. 3B or FIG. 4B.

[0112] As a general rule, and as shown in FIG. 8A, the cutting head 30is provided with a protective cover 84. This cover is open when themachine is stopped and an operator is working on the cutting head, forexample replacing the cutting wheel 32.

[0113] As shown in FIG. 8B, the dimensions of the system are preferablysuch that the cover 84 intersects the optical path 51 when it is not inits closed position. The output signal of the sensor 52 is then greatlymodified, leading to stopping of cutting. Thus unintentional opening ofthe cover 84 while the system is operating is prevented. Similarly, anypremature intervention by an operator while the cutting system is stillactive leads to total shutting down of the system and stopping ofcutting, even if the boom 22 and the carriage 35 are stationary.

[0114] In another embodiment, shown in FIG. 9, the lateral bars fordetecting obstacles each have a first part 90, 92 and an independentsecond part 100, 102. For example, an obstacle on the element 102modifies the position of that element relative to the boom 22, withoutthe relative position of the latter and the element 92 being modified.Each of the elements 90, 92, 100, 102 is provided with a systemcomprising a slot and an electromechanical switch, such as the system39-41 from FIG. 2, for example. Displacement of either of these elementsrelative to the boom 22 trips the switch and stops the cutting machine,as already explained hereinabove.

[0115] What is more, optical systems can also detect movement of each ofthese elements relative to the facing element and relative to the boom22.

[0116] For example, the element 90 can be provided with an emitter whichemits a beam that is received by a receiver carried by the element 92.Movement of one of these elements relative to the other leads to asudden variation in the output signal of the receiver and, once again,stopping of the drive system of the boom 22. It is also possible toprovide an emitter and a receiver on one of the elements 90, 92 and toprovide the other element with a reflector system, as in FIG. 4A or FIG.4B.

[0117] The same type of sensor system can be provided on the elements100, 102.

[0118]FIG. 9 shows an embodiment in which each of the elements 90, 92,100, 102 is provided with an emitter 98, 110, 114, 118 and a receiver108, 112, 116, 120. These optical systems are combined with reflectorelements 95, 97, 93, 99 fixed by connections 94, 96 to the ends of thesupport 35 for the cutting head.

[0119] If the position of any of the bars 90, 92, 100, 102 is modifiedby the presence of a lateral obstacle, the output signal of thecorresponding sensor varies suddenly, which leads to stopping of thedrive system of the boom 22. This embodiment can further identify theposition relative to the boom 22 of an obstacle situated on the path ofone of the beams emitted by one of the emitters or reflected toward oneof the sensors. It is possible to determine if the obstacle is in frontof or behind the boom 22 (in the direction of the axis X) or in theright-hand part or the left-hand part of the boom (in the direction ofthe axis Y), according to which beam is interrupted. This informationcan be displayed on the display screen of a data processing system suchas the system 34 shown in FIG. 1A, for example. The cutting table may berelatively large and it may be useful for an operator near the console34 to be informed immediately of the position of an object on thecutting table, without the operator having to move nearer the boom 22.

[0120] This also makes it possible to store problems encountered whenexecuting cutting operations. Any such problems can then be dealt withmore effectively at a later time, for example, and productivityimproved, in particular by improving materials handling around themachine.

[0121] The invention has been described in an application to a fixedtable. It can equally well be applied to a cutting system with a movingtable.

[0122] A moving table, incorporating a conveyor, has an overallstructure similar to that described above in connection with FIG. 1A,for example. The cutting surface can be a material supporting andconveying system, as shown diagrammatically in FIG. 10.

[0123] The system comprises:

[0124] a cutting support 192 comprising a microperforated polyurethanebelt for conveying the material running around two idler shafts 194,196,

[0125] a table 198 under the belt provided with perforated, juxtaposedand transversely mounted boxes and surmounted by a perforated plateserving as a support for the microperforated belt, and

[0126] a suction system 200 connected to each box, the combinationholding the material down on the surface of the table by suction.

[0127] In another embodiment with a moving table, the cutting surface isa bristle mat comprising juxtaposed blocks on rails sliding on a chainrunning around two shafts. This kind of system is described in U.S. Pat.No. 4,328,726, for example.

[0128] The safety system according to the invention and the movingassembly according to the invention, combining electromechanical lateralobstacle sensor systems with optical systems fixed to the lateralobstacle sensor systems, have the same advantages as in the case of afixed table.

[0129] The invention has been described with infrared emitter/receivertype optical systems. It is equally possible to use otheremitter/receiver systems operating in other ranges of wavelengths (thevisible spectrum, for example), the emitter being a laser source ordiode, for example.

1. A moving assembly for a working system, said assembly comprising: aboom (22) extending along an axis between first and second ends (31, 33)and a working head (30) mounted on said boom; first and second lateralobstacle sensor systems (40, 42, 77, 83, 90, 92, 100, 102) mounted ateach end of the boom, movable or deformable relative to the boom andindependently of each other in the direction of an axis (X)substantially perpendicular to the axis of the boom, and having anextension in the same direction on either side of the boom; andrespective first and second optical systems (50, 52, 60, 62, 75, 79)fixed to the first and second lateral obstacle sensor systems to detectthe presence of an obstacle on the path of the boom and movement and/ordeformation of the lateral obstacle sensor systems relative to eachother.
 2. A moving assembly according to claim 1, wherein the first andsecond optical systems respectively comprise a radiation emitter (50,60, 64, 98, 110, 114, 118) and a radiation sensor (52, 82, 64, 75, 79,108, 112, 116, 120).
 3. A moving assembly according to claim 2,comprising two radiation emitters (50, 60) and two radiation sensors(52, 62, 75, 79) and wherein each detector is associated with anemitter.
 4. A moving assembly according to claim 2 or claim 3, whereinan emitter is fixed to one of the lateral obstacle sensor systems andthe associated sensor is fixed to the other lateral obstacle sensorsystem.
 5. A moving assembly according to either claim 2 or claim 3,wherein an emitter and the associated sensor (64, 66) are fixed to thesame lateral obstacle sensor system and a reflector system (68) is fixedto the other lateral obstacle sensor system.
 6. A moving assemblyaccording to claim 2 or claim 3, wherein an emitter and the associatedsensor are fixed to one end (33) of the boom (22) and a reflector system(68) is fixed either to the lateral obstacle sensor system at the otherend (31) of the boom or to the other end (31) of the boom.
 7. A movingassembly according to any one of claims 1 to 6, further includingoptical systems (72, 74) for detecting obstacles on the path of the boomand wherein each optical system is mounted on the boom by means of arigid or deformable connection (73, 75, 83).
 8. A moving assemblyaccording to claim 7, wherein the obstacle sensing optical systemsmounted on the boom include a first radiation emitter (72) and a firstradiation sensor (74).
 9. A moving assembly according to claim 8,wherein the first radiation emitter (72) and the first radiation sensor(74) are respectively fixed to a first end and to a second end of theboom.
 10. A moving assembly according to claim 8, wherein the firstradiation emitter and the first radiation sensor are fixed to the sameend of the boom and a reflector system is fixed to the other end of theboom to reflect radiation from the first emitter toward the firstsensor.
 11. A moving assembly according to any one of claims 7 to 10,wherein a safety volume around the boom is defined by the first andsecond fixed optical systems (50, 52, 60, 62) on the first and secondlateral obstacle sensor systems (40, 42) and the optical systems (72,74)mounted on the boom.
 12. A system according to any one of claims 1 to11, wherein the first and second lateral obstacle sensor systems (40,42, 90, 92, 100, 102) are movable relative to the boom and independentlyof each other in said direction (X) substantially perpendicular to theaxis of the boom.
 13. A system according to claim 12, further includingrespective first and second movement sensors (39, 41) associated withthe first and second sensor systems for sensing obstacles that arelaterally disposed relative to the boom.
 14. A system according to claim13, wherein the respective first and second movement sensor systems (39,41) associated with the first and second lateral obstacle sensor systemsinclude an electromechanical sensor (41).
 15. A system according to anyone of claims 12 to 14, wherein the first and second lateral obstaclesensor systems (40, 42) further include a support (77) mounted on thefirst and/or second lateral obstacle sensor system and an optical system(75) fixed to the support (77) to detect obstacles when the boom moves.16. A system according to claim 15, wherein the support (77) isdeformable in said direction along an axis (X) perpendicular to the axisof the boom and the optical systems (75) mounted on the support candetect deformation of said support along the axis (X).
 17. A movingassembly according to any one of claims 12 to 16, wherein the firstand/or second lateral obstacle sensor system has a first part (40-1)movable in the direction of said axis (X) substantially perpendicular tothe axis of the boom and a second part (40-2) articulated to the firstpart and able to rotate about an axis substantially perpendicular tosaid direction and the first or second optical system (50) is fixed tothe second part.
 18. A system according to any one of claims 12 to 17,wherein the first lateral obstacle sensor system has first and secondparts (90, 100) moveable relative to each other and each provided withoptical systems (98, 108, 114, 116) for detecting an obstacle on thepath of the boom and movement of one of the lateral obstacle sensorsystems relative to the other one.
 19. A system according to claim 18,wherein the second lateral obstacle sensor system has third and fourthparts (92, 102) moveable relative to each other and each provided withoptical systems (110, 112, 118, 120) for detecting the presence of anobstacle on the path of the boom and movement of one of the lateralobstacle sensor systems relative to the other one.
 20. A systemaccording to any one of claims 1 to 11, wherein at least one of thefirst and second lateral obstacle sensor systems (83) is deformable inat least one direction (X) perpendicular to the axis of the boom.
 21. Asystem according to claim 20, wherein the deformable lateral obstaclesensor system comprises a deformable support (83) on which the opticalsystems (79) for detecting obstacles and deformation of the deformablesupport are mounted.
 22. A system according to claim 20 or claim 21,further comprising optical systems mounted on the deformable lateralobstacle sensor system(s) and with the first and second optical systemsdefining a safety volume around the boom.
 23. A moving assemblyaccording to any one of claims 1 to 22, wherein the first and secondoptical systems respectively fixed to the first and second lateralobstacle sensor systems define an optical path through an opticalelement (80) connected to the working head (30) whose position relativeto said head varies if said element encounters an obstacle duringmovement of the boom (22) and/or the working head (30).
 24. A movingassembly according to claim 23, wherein the optical element (80) ismounted on a structure comprising a support element (37) on the workinghead (30) or on a carriage (35) on which the working head is mounted.25. A moving assembly according to claim 24, wherein the support elementtakes the form of a hoop (87, 89).
 26. A moving assembly according toclaim 25, including a plurality of support elements taking the form ofhoops (87, 89) defining a hemispherical or cylindrical envelope aroundthe working head (30) and/or the carriage (35).
 27. A moving assemblyaccording to claim 26, wherein the hemispherical or cylindrical envelopeis movable in rotation and/or in translation relative to the workinghead (30) or the carriage (35).
 28. A moving assembly according to anyone of claims 1 to 27, wherein the working head (30) includes aprotective cover (84) which protects it when it is closed and whichintersects an optical path (51) defined between the first and secondoptical systems (50, 52) fixed to the first and second lateral obstaclesensor systems.
 29. A system for processing flexible materials, thesystem comprising: a work support or table (2, 92); one or more movingassemblies according to any one of claims 1 to 27; and a system formoving said moving assembly or assemblies on the work support or table.30. A processing system according to claim 29, further comprising asystem for stopping the system for moving the moving assembly if theoptical system detects the presence of an obstacle on the path of theboom or movement or deformation of one of the lateral obstacle sensorsystems.
 31. A processing system according to claim 29 or claim 30,wherein the work support or table (2) is fixed.
 32. A processing systemaccording to claim 29 or claim 30, wherein the work support or table(92) incorporates a moving conveyor.
 33. A processing system accordingto any one of claims 29 to 32, wherein the working head of the movingassembly supports a cutting tool and/or a printing tool and/or alabeling tool and/or a perforation tool.